mod/dfrn_poll.php

   1 <?php
   2
   3 /**
   4  * @file mod/dfrn_poll.php
   5  */
   6
   7 use Friendica\App;
   8 use Friendica\Core\Config;
   9 use Friendica\Core\L10n;
  10 use Friendica\Core\Logger;
  11 use Friendica\Core\System;
  12 use Friendica\Core\Session;
  13 use Friendica\Database\DBA;
  14 use Friendica\Module\Login;
  15 use Friendica\Protocol\DFRN;
  16 use Friendica\Protocol\OStatus;
  17 use Friendica\Util\Network;
  18 use Friendica\Util\Strings;
  19 use Friendica\Util\XML;
  20
  21 function dfrn_poll_init(App $a)
  22 {
  23         Login::sessionAuth();
  24
  25         $dfrn_id         =  $_GET['dfrn_id']         ?? '';
  26         $type            = ($_GET['type']            ?? '') ?: 'data';
  27         $last_update     =  $_GET['last_update']     ?? '';
  28         $destination_url =  $_GET['destination_url'] ?? '';
  29         $challenge       =  $_GET['challenge']       ?? '';
  30         $sec             =  $_GET['sec']             ?? '';
  31         $dfrn_version    = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
  32         $quiet                   = !empty($_GET['quiet']);
  33
  34         // Possibly it is an OStatus compatible server that requests a user feed
  35         $user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
  36         if (($a->argc > 1) && ($dfrn_id == '') && !strstr($user_agent, 'Friendica')) {
  37                 $nickname = $a->argv[1];
  38                 header("Content-type: application/atom+xml");
  39                 echo OStatus::feed($nickname, $last_update, 10);
  40                 exit();
  41         }
  42
  43         $direction = -1;
  44
  45         if (strpos($dfrn_id, ':') == 1) {
  46                 $direction = intval(substr($dfrn_id, 0, 1));
  47                 $dfrn_id = substr($dfrn_id, 2);
  48         }
  49
  50         $hidewall = false;
  51
  52         if (($dfrn_id === '') && empty($_POST['dfrn_id'])) {
  53                 if (Config::get('system', 'block_public') && !Session::isAuthenticated()) {
  54                         throw new \Friendica\Network\HTTPException\ForbiddenException();
  55                 }
  56
  57                 $user = '';
  58                 if ($a->argc > 1) {
  59                         $r = q("SELECT `hidewall`,`nickname` FROM `user` WHERE `user`.`nickname` = '%s' LIMIT 1",
  60                                 DBA::escape($a->argv[1])
  61                         );
  62                         if (!$r) {
  63                                 throw new \Friendica\Network\HTTPException\NotFoundException();
  64                         }
  65
  66                         $hidewall = ($r[0]['hidewall'] && !local_user());
  67
  68                         $user = $r[0]['nickname'];
  69                 }
  70
  71                 Logger::log('dfrn_poll: public feed request from ' . $_SERVER['REMOTE_ADDR'] . ' for ' . $user);
  72                 header("Content-type: application/atom+xml");
  73                 echo DFRN::feed('', $user, $last_update, 0, $hidewall);
  74                 exit();
  75         }
  76
  77         if (($type === 'profile') && (!strlen($sec))) {
  78                 $sql_extra = '';
  79                 switch ($direction) {
  80                         case -1:
  81                                 $sql_extra = sprintf(" AND ( `dfrn-id` = '%s' OR `issued-id` = '%s' ) ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
  82                                 $my_id = $dfrn_id;
  83                                 break;
  84                         case 0:
  85                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  86                                 $my_id = '1:' . $dfrn_id;
  87                                 break;
  88                         case 1:
  89                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  90                                 $my_id = '0:' . $dfrn_id;
  91                                 break;
  92                         default:
  93                                 $a->internalRedirect();
  94                                 break; // NOTREACHED
  95                 }
  96
  97                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
  98                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
  99                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
 100                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
 101                         DBA::escape($a->argv[1])
 102                 );
 103
 104                 if (DBA::isResult($r)) {
 105                         $s = Network::fetchUrl($r[0]['poll'] . '?dfrn_id=' . $my_id . '&type=profile-check');
 106
 107                         Logger::log("dfrn_poll: old profile returns " . $s, Logger::DATA);
 108
 109                         if (strlen($s)) {
 110                                 $xml = XML::parseString($s);
 111
 112                                 if ((int)$xml->status === 1) {
 113                                         $_SESSION['authenticated'] = 1;
 114                                         $_SESSION['visitor_id'] = $r[0]['id'];
 115                                         $_SESSION['visitor_home'] = $r[0]['url'];
 116                                         $_SESSION['visitor_handle'] = $r[0]['addr'];
 117                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 118                                         $_SESSION['my_url'] = $r[0]['url'];
 119
 120                                         Session::setVisitorsContacts();
 121
 122                                         if (!$quiet) {
 123                                                 info(L10n::t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 124                                         }
 125
 126                                         // Visitors get 1 day session.
 127                                         $session_id = session_id();
 128                                         $expire = time() + 86400;
 129                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 130                                                 DBA::escape($expire),
 131                                                 DBA::escape($session_id)
 132                                         );
 133                                 }
 134                         }
 135
 136                         $profile = (count($r) > 0 && isset($r[0]['nickname']) ? $r[0]['nickname'] : '');
 137                         if (!empty($destination_url)) {
 138                                 System::externalRedirect($destination_url);
 139                         } else {
 140                                 $a->internalRedirect('profile/' . $profile);
 141                         }
 142                 }
 143                 $a->internalRedirect();
 144         }
 145
 146         if ($type === 'profile-check' && $dfrn_version < 2.2) {
 147                 if ((strlen($challenge)) && (strlen($sec))) {
 148                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 149                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 150                                 DBA::escape($sec)
 151                         );
 152                         if (!DBA::isResult($r)) {
 153                                 System::xmlExit(3, 'No ticket');
 154                                 // NOTREACHED
 155                         }
 156
 157                         $orig_id = $r[0]['dfrn_id'];
 158                         if (strpos($orig_id, ':')) {
 159                                 $orig_id = substr($orig_id, 2);
 160                         }
 161
 162                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 163                                 intval($r[0]['cid'])
 164                         );
 165                         if (!DBA::isResult($c)) {
 166                                 System::xmlExit(3, 'No profile');
 167                         }
 168
 169                         $contact = $c[0];
 170
 171                         $sent_dfrn_id = hex2bin($dfrn_id);
 172                         $challenge = hex2bin($challenge);
 173
 174                         $final_dfrn_id = '';
 175
 176                         if (($contact['duplex']) && strlen($contact['prvkey'])) {
 177                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 178                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 179                         } else {
 180                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 181                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 182                         }
 183
 184                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 185
 186                         if (strpos($final_dfrn_id, ':') == 1) {
 187                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 188                         }
 189
 190                         if ($final_dfrn_id != $orig_id) {
 191                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 192                                 // did not decode properly - cannot trust this site
 193                                 System::xmlExit(3, 'Bad decryption');
 194                         }
 195
 196                         header("Content-type: text/xml");
 197                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 198                         exit();
 199                         // NOTREACHED
 200                 } else {
 201                         // old protocol
 202                         switch ($direction) {
 203                                 case 1:
 204                                         $dfrn_id = '0:' . $dfrn_id;
 205                                         break;
 206                                 case 0:
 207                                         $dfrn_id = '1:' . $dfrn_id;
 208                                         break;
 209                                 default:
 210                                         break;
 211                         }
 212
 213                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 214                         $r = q("SELECT * FROM `profile_check` WHERE `dfrn_id` = '%s' ORDER BY `expire` DESC",
 215                                 DBA::escape($dfrn_id));
 216                         if (DBA::isResult($r)) {
 217                                 System::xmlExit(1);
 218                                 return; // NOTREACHED
 219                         }
 220                         System::xmlExit(0);
 221                         return; // NOTREACHED
 222                 }
 223         }
 224 }
 225
 226 function dfrn_poll_post(App $a)
 227 {
 228         $dfrn_id      =  $_POST['dfrn_id']   ?? '';
 229         $challenge    =  $_POST['challenge'] ?? '';
 230         $url          =  $_POST['url']       ?? '';
 231         $sec          =  $_POST['sec']       ?? '';
 232         $ptype        =  $_POST['type']      ?? '';
 233         $perm         = ($_POST['perm']      ?? '') ?: 'r';
 234         $dfrn_version = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
 235
 236         if ($ptype === 'profile-check') {
 237                 if (strlen($challenge) && strlen($sec)) {
 238                         Logger::log('dfrn_poll: POST: profile-check');
 239
 240                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 241                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 242                                 DBA::escape($sec)
 243                         );
 244                         if (!DBA::isResult($r)) {
 245                                 System::xmlExit(3, 'No ticket');
 246                                 // NOTREACHED
 247                         }
 248
 249                         $orig_id = $r[0]['dfrn_id'];
 250                         if (strpos($orig_id, ':')) {
 251                                 $orig_id = substr($orig_id, 2);
 252                         }
 253
 254                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 255                                 intval($r[0]['cid'])
 256                         );
 257                         if (!DBA::isResult($c)) {
 258                                 System::xmlExit(3, 'No profile');
 259                         }
 260
 261                         $contact = $c[0];
 262
 263                         $sent_dfrn_id = hex2bin($dfrn_id);
 264                         $challenge = hex2bin($challenge);
 265
 266                         $final_dfrn_id = '';
 267
 268                         if ($contact['duplex'] && strlen($contact['prvkey'])) {
 269                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 270                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 271                         } else {
 272                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 273                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 274                         }
 275
 276                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 277
 278                         if (strpos($final_dfrn_id, ':') == 1) {
 279                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 280                         }
 281
 282                         if ($final_dfrn_id != $orig_id) {
 283                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 284                                 // did not decode properly - cannot trust this site
 285                                 System::xmlExit(3, 'Bad decryption');
 286                         }
 287
 288                         header("Content-type: text/xml");
 289                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 290                         exit();
 291                         // NOTREACHED
 292                 }
 293         }
 294
 295         $direction = -1;
 296         if (strpos($dfrn_id, ':') == 1) {
 297                 $direction = intval(substr($dfrn_id, 0, 1));
 298                 $dfrn_id = substr($dfrn_id, 2);
 299         }
 300
 301         $r = q("SELECT * FROM `challenge` WHERE `dfrn-id` = '%s' AND `challenge` = '%s' LIMIT 1",
 302                 DBA::escape($dfrn_id),
 303                 DBA::escape($challenge)
 304         );
 305
 306         if (!DBA::isResult($r)) {
 307                 exit();
 308         }
 309
 310         $type = $r[0]['type'];
 311         $last_update = $r[0]['last_update'];
 312
 313         DBA::delete('challenge', ['dfrn-id' => $dfrn_id, 'challenge' => $challenge]);
 314
 315         $sql_extra = '';
 316         switch ($direction) {
 317                 case -1:
 318                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 319                         break;
 320                 case 0:
 321                         $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 322                         break;
 323                 case 1:
 324                         $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 325                         break;
 326                 default:
 327                         $a->internalRedirect();
 328                         break; // NOTREACHED
 329         }
 330
 331         $r = q("SELECT * FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 $sql_extra LIMIT 1");
 332         if (!DBA::isResult($r)) {
 333                 exit();
 334         }
 335
 336         $contact = $r[0];
 337         $owner_uid = $r[0]['uid'];
 338         $contact_id = $r[0]['id'];
 339
 340         if ($type === 'reputation' && strlen($url)) {
 341                 $r = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
 342                         DBA::escape($url),
 343                         intval($owner_uid)
 344                 );
 345                 $reputation = 0;
 346                 $text = '';
 347
 348                 if (DBA::isResult($r)) {
 349                         $reputation = $r[0]['rating'];
 350                         $text = $r[0]['reason'];
 351
 352                         if ($r[0]['id'] == $contact_id) { // inquiring about own reputation not allowed
 353                                 $reputation = 0;
 354                                 $text = '';
 355                         }
 356                 }
 357
 358                 echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
 359                 <reputation>
 360                         <url>$url</url>
 361                         <rating>$reputation</rating>
 362                         <description>$text</description>
 363                 </reputation>
 364                 ";
 365                 exit();
 366                 // NOTREACHED
 367         } else {
 368                 // Update the writable flag if it changed
 369                 Logger::log('dfrn_poll: post request feed: ' . print_r($_POST, true), Logger::DATA);
 370                 if ($dfrn_version >= 2.21) {
 371                         if ($perm === 'rw') {
 372                                 $writable = 1;
 373                         } else {
 374                                 $writable = 0;
 375                         }
 376
 377                         if ($writable != $contact['writable']) {
 378                                 q("UPDATE `contact` SET `writable` = %d WHERE `id` = %d",
 379                                         intval($writable),
 380                                         intval($contact_id)
 381                                 );
 382                         }
 383                 }
 384
 385                 header("Content-type: application/atom+xml");
 386                 $o = DFRN::feed($dfrn_id, $a->argv[1], $last_update, $direction);
 387                 echo $o;
 388                 exit();
 389         }
 390 }
 391
 392 function dfrn_poll_content(App $a)
 393 {
 394         $dfrn_id         =  $_GET['dfrn_id']         ?? '';
 395         $type            = ($_GET['type']            ?? '') ?: 'data';
 396         $last_update     =  $_GET['last_update']     ?? '';
 397         $destination_url =  $_GET['destination_url'] ?? '';
 398         $sec             =  $_GET['sec']             ?? '';
 399         $dfrn_version    = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
 400         $quiet           = !empty($_GET['quiet']);
 401
 402         $direction = -1;
 403         if (strpos($dfrn_id, ':') == 1) {
 404                 $direction = intval(substr($dfrn_id, 0, 1));
 405                 $dfrn_id = substr($dfrn_id, 2);
 406         }
 407
 408         if ($dfrn_id != '') {
 409                 // initial communication from external contact
 410                 $hash = Strings::getRandomHex();
 411
 412                 $status = 0;
 413
 414                 DBA::delete('challenge', ["`expire` < ?", time()]);
 415
 416                 if ($type !== 'profile') {
 417                         q("INSERT INTO `challenge` ( `challenge`, `dfrn-id`, `expire` , `type`, `last_update` )
 418                                 VALUES( '%s', '%s', '%s', '%s', '%s' ) ",
 419                                 DBA::escape($hash),
 420                                 DBA::escape($dfrn_id),
 421                                 intval(time() + 60 ),
 422                                 DBA::escape($type),
 423                                 DBA::escape($last_update)
 424                         );
 425                 }
 426
 427                 $sql_extra = '';
 428                 switch ($direction) {
 429                         case -1:
 430                                 if ($type === 'profile') {
 431                                         $sql_extra = sprintf(" AND (`dfrn-id` = '%s' OR `issued-id` = '%s') ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
 432                                 } else {
 433                                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 434                                 }
 435
 436                                 $my_id = $dfrn_id;
 437                                 break;
 438                         case 0:
 439                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 440                                 $my_id = '1:' . $dfrn_id;
 441                                 break;
 442                         case 1:
 443                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 444                                 $my_id = '0:' . $dfrn_id;
 445                                 break;
 446                         default:
 447                                 $a->internalRedirect();
 448                                 break; // NOTREACHED
 449                 }
 450
 451                 $nickname = $a->argv[1];
 452
 453                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
 454                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
 455                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
 456                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
 457                         DBA::escape($nickname)
 458                 );
 459                 if (DBA::isResult($r)) {
 460                         $challenge = '';
 461                         $encrypted_id = '';
 462                         $id_str = $my_id . '.' . mt_rand(1000, 9999);
 463
 464                         if (($r[0]['duplex'] && strlen($r[0]['pubkey'])) || !strlen($r[0]['prvkey'])) {
 465                                 openssl_public_encrypt($hash, $challenge, $r[0]['pubkey']);
 466                                 openssl_public_encrypt($id_str, $encrypted_id, $r[0]['pubkey']);
 467                         } else {
 468                                 openssl_private_encrypt($hash, $challenge, $r[0]['prvkey']);
 469                                 openssl_private_encrypt($id_str, $encrypted_id, $r[0]['prvkey']);
 470                         }
 471
 472                         $challenge = bin2hex($challenge);
 473                         $encrypted_id = bin2hex($encrypted_id);
 474                 } else {
 475                         $status = 1;
 476                         $challenge = '';
 477                         $encrypted_id = '';
 478                 }
 479
 480                 if (($type === 'profile') && (strlen($sec))) {
 481                         // heluecht: I don't know why we don't fail immediately when the user or contact hadn't been found.
 482                         // Since it doesn't make sense to continue from this point on, we now fail here. This should be safe.
 483                         if (!DBA::isResult($r)) {
 484                                 throw new \Friendica\Network\HTTPException\NotFoundException();
 485                         }
 486
 487                         // URL reply
 488                         if ($dfrn_version < 2.2) {
 489                                 $s = Network::fetchUrl($r[0]['poll']
 490                                         . '?dfrn_id=' . $encrypted_id
 491                                         . '&type=profile-check'
 492                                         . '&dfrn_version=' . DFRN_PROTOCOL_VERSION
 493                                         . '&challenge=' . $challenge
 494                                         . '&sec=' . $sec
 495                                 );
 496                         } else {
 497                                 $s = Network::post($r[0]['poll'], [
 498                                         'dfrn_id' => $encrypted_id,
 499                                         'type' => 'profile-check',
 500                                         'dfrn_version' => DFRN_PROTOCOL_VERSION,
 501                                         'challenge' => $challenge,
 502                                         'sec' => $sec
 503                                 ])->getBody();
 504                         }
 505
 506                         Logger::log("dfrn_poll: sec profile: " . $s, Logger::DATA);
 507
 508                         if (strlen($s) && strstr($s, '<?xml')) {
 509                                 $xml = XML::parseString($s);
 510
 511                                 Logger::log('dfrn_poll: profile: parsed xml: ' . print_r($xml, true), Logger::DATA);
 512
 513                                 Logger::log('dfrn_poll: secure profile: challenge: ' . $xml->challenge . ' expecting ' . $hash);
 514                                 Logger::log('dfrn_poll: secure profile: sec: ' . $xml->sec . ' expecting ' . $sec);
 515
 516                                 if (((int) $xml->status == 0) && ($xml->challenge == $hash) && ($xml->sec == $sec)) {
 517                                         $_SESSION['authenticated'] = 1;
 518                                         $_SESSION['visitor_id'] = $r[0]['id'];
 519                                         $_SESSION['visitor_home'] = $r[0]['url'];
 520                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 521                                         $_SESSION['my_url'] = $r[0]['url'];
 522
 523                                         Session::setVisitorsContacts();
 524
 525                                         if (!$quiet) {
 526                                                 info(L10n::t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 527                                         }
 528
 529                                         // Visitors get 1 day session.
 530                                         $session_id = session_id();
 531                                         $expire = time() + 86400;
 532                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 533                                                 DBA::escape($expire),
 534                                                 DBA::escape($session_id)
 535                                         );
 536                                 }
 537                         }
 538
 539                         $profile = ((DBA::isResult($r) && $r[0]['nickname']) ? $r[0]['nickname'] : $nickname);
 540
 541                         switch ($destination_url) {
 542                                 case 'profile':
 543                                         $a->internalRedirect('profile/' . $profile . '?f=&tab=profile');
 544                                         break;
 545                                 case 'photos':
 546                                         $a->internalRedirect('photos/' . $profile);
 547                                         break;
 548                                 case 'status':
 549                                 case '':
 550                                         $a->internalRedirect('profile/' . $profile);
 551                                         break;
 552                                 default:
 553                                         $appendix = (strstr($destination_url, '?') ? '&f=&redir=1' : '?f=&redir=1');
 554                                         $a->redirect($destination_url . $appendix);
 555                                         break;
 556                         }
 557                         // NOTREACHED
 558                 } else {
 559                         // XML reply
 560                         header("Content-type: text/xml");
 561                         echo '<?xml version="1.0" encoding="UTF-8"?>' . "\r\n"
 562                                 . '<dfrn_poll>' . "\r\n"
 563                                 . "\t" . '<status>' . $status . '</status>' . "\r\n"
 564                                 . "\t" . '<dfrn_version>' . DFRN_PROTOCOL_VERSION . '</dfrn_version>' . "\r\n"
 565                                 . "\t" . '<dfrn_id>' . $encrypted_id . '</dfrn_id>' . "\r\n"
 566                                 . "\t" . '<challenge>' . $challenge . '</challenge>' . "\r\n"
 567                                 . '</dfrn_poll>' . "\r\n";
 568                         exit();
 569                         // NOTREACHED
 570                 }
 571         }
 572 }